Ch 4. ECOLOGY (4.1 Species, communities and ecosystems (Consumers:
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Interbreeding:When two members of the same species mate and produce offspring.

PopulationGroup of organisms of the same species who live in the same area at the same time.

If two populations live in different areas they are unlikely to interbreed with each other. This does not mean that they are different species. If they potentially could interbreed, they are still members of the same species.

If two populations of a species never interbreed ten they may gradually develop differences in their characters. Even if there are recognisable differences, they are considered to be the same species until they cannot interbreed and produce fertile offspring.

Autotrophic and Heterotrophic NutritionSpecies have either an autotrophic or heterotrophic method of nutrition (but a few have both methods).

All organisms need a supply of organic nutrients, such as glucose ad amino acids, needed for growth and reproduction. Methods of obtaining these carbon compounds can be divided into two types:

Autotrophic:

Self-feeding

Some organisms make their own carbon compounds from other organisms.

Heterotrophic:

Feeding on others

Some organisms obtain their carbon compounds from other organisms

Some unicellular organisms use both methods of nutrition.

For example:
- Euglena gracilis has chloroplasts and carries out photosynthesis when there is sufficient light.
- However, it can also feed on detritus or smaller organisms by endocytosis.

Mixotrophic:Organisms that are not exclusively autotrophic or heterotrophic.

Consumers:Heterotrophs that feed on living organisms by ingestion.

Consumers ingest their food. This means that they take in undigested material from other organisms. They digest it and absorb the products of digestion.

Unicellular consumers such as Paramecium take the food in by endocytosis and digest it inside vacuoles.

Multicellular consumers such as humans or lions take food into their digestive systems by swallowing it.

Consumers are sometimes divided up into trophic groups, according to what other organisms they consume.Primary consumers feed on autotrophs; secondary consumers feed on primary consumers and so on.In practive, most consumers do not fit neatly into any one of these groups because their diet includes material from a variety of trophic groups. #

Detritivores:Heterotrophs that obtain organic nutrients from detritus by internal ingestion.

Organisms discard large quantities of organic matter, such as:

dead leaves and other parts of plants

feathers, hairs and other dead parts of animal bodies

faeces from animals

This dead organic matter rarely accumulates in ecosystems and instead is used as a source of nutrition by two groups of heterotroph - detritivores and saprotrophs

Detritivores ingest dead organic matter and then digest it internally and absorb the products of digestion.

Large multicellular detritivores such as earthworms ingest the dead matter into their gut.

Unicellular organisms ingest it into food vacuoles.

The larvae of dung beetles feed by ingestion of faeces rolled into a ball by their parents.

Many types of bacteria and fungi are saprotrophic.They are also known as decomposers because they break down carbon compounds in dead organic matter and release elements such as nitrogen into the ecosystem so that they can be used again by other organisms.

CommunitiesGroups of populations live together. A group of populations living together in an area and interacting with each other is known in ecology as a community.

AutotrophySelf-feedingOrganisms which produce their own food from organic molecules.

Producers

PHOTOAUTOTROPHY(photosynthesis)Green plants, phytoplankton and algae

CHEMOAUTOTROPHY(chemosynthesis)Deep-sea chemosynthetic bacteria

HeterotrophyOther source feedingOrganisms which derive energy from other living organisms.

ConsumersIngest organic matter which is living or recently killed

Primary eat producers(Herbivores)

Secondary eat other consumers(Carnivores, omnivores)

DecomposersDerive energy from non-living organic matter

DetritivoresIngest non-living organic mater(earthworms, woodlice)

Saprotrophslives in or on non-living organic matter, secreting digestive enzymes into it and absorbing digestive products.(bacteria and fungi)

Adaptations (5.2)

Adaptations are characteristics that make an individual suited to its environment and way of life. Adaptations are result of evolution - a change in a species over long periods of time.

Types of Adaptations:

Structural:Physical features of an organism, like body shape, spines, appendages, etc.

Functional:Physiological features which allow survival for example ability to regulate their bodily functions (e.g. breathing and temperature) and perform special functions like excreting chemicals as a defence mechanism.